Pump



J. E. BEVINS March 13, 1951 PUMP 2 Shees-Sheet 1 Filed June 21, 1946 March 13, 1951 J. E. BEvlNs 2,544,976

' PUMP Filed June 2l, 1946 2 Sheets-Sheet 2 IOO n .g `c-unes L'. Bevp'ns;

Patented Mar. 13, 1.951

UNITED suplir-Es` ATENT OFFICE PUMP Y l James E. Bevins, Ramsey Estates, N. J., assigner I t Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application June 21, 1946, serial No. 678,481 Y I 11 Claims.

l This invention relates to pumps and the like, particularly of the cylinder'and piston type, and

Vto novel means for sealing the pistons relative to the cylinders.

A pump piston of standard type, operating in a cylinder of uniform bore, has heretofore been sealed against leakage through the clearance between the piston and the cylinder wall, as by where the fluid is of low viscosity and lubricity.

Structures have also been suggested to seal pump pistons against such leakage by the counterpressure of a sealing iiuid, but such pressure has been controlled separately from, and independently of, the pressure of the uid being pumped, with the result `that the structures are complicated, cylinders of different bores are required, and the pressure regulating means, when set for a certainl pressure, is not effective at other pressures unless reset by hand, which is not feasible in a pump vcalled upon to operate at different pressures. s. l

Devices for pumping fluid of low viscosity, such as gasoline, have required extremely close ttingAparnts'to create high pressures, such fit being d ifcult and expensive to produce, and subject to early ineffectiveness from Awear whereby the fluid leaks past the piston to* lower 'the quantity and pressure of the fluid being delivered.

An object of the invention is to provide a pump of the aforementioned character which remedies the faults stated, and does so by novel improved means.A

Ant'herobject is vto provide means including a'pistonunit or'the like in which the unit comprises a'plurality of piston elements movable together zto effect the unit pumping-action, and which elements have pumping action Vrelative to each other 'dependent upon the pressure of the uid Vbeing'pumped toforce a sealing fluid into positionsealing the unit at a pressure preventing the passage of Iany substantial amount of either fluid past the piston.v l i Another object is to provide a unit, as aforesaid, which is adapted to-operate in a cylinder portion of one uniform'bore.

Another object `is to provide novel means adapted to pump fluid and to'seal a movable pumping element or piston therefor againstfleakage of 2 ysuch fluid past such element from its pumping'l side to its oppositeside, "and providing'such element with greater clearance relative to a cylinder or chamber wall vthan such fluid would normally require for such sealing. Y f

Another object is to provide a novel movable pump unit or piston, in which the unit ispro vided with means forming a fluid pistonring or the like instead of the usual ring of metal.

Another object is to provide novel operating means for the piston unit, such as an eccentric cam having passageway means through which the passage of sealing fluid is controlled in pre- .determined` relation to a position of the piston :during its stroke.A

A further object is to provide a pump of the above-indicated character that is simple and durable in construction, economical to manufacture, and effective in its operation.

These and other objects and features of the invention are pointed out in'the following description in terms of the embodiment thereof which is shown in the accompanying drawings. It is to be understood, however, that the drawings are for the purpose of illustration only,` and are not designed as a definition of the limitsof the invention, reference being had to the appended In the drawingsgwherein like reference characters refer to like parts in the several views:

Figure 1 is a view, partially in end elevation and partially in section, along a line I,-I of Figure 3, of a pump constructed in accordance with ione form of the invention;

Figure 2 is a detail of certain` parts, as seen in Figure 3; L 'L 1 Figure 3 is a viewpartially in endM elevation and y rpartially in sectionV substantially along the gline 3-3ofFigure1;and I Figure 4 is a view similar to Figure 2 of a modified form of the structurethereof. ,1

Referring to Figuresland, one form of pump embodying ,the invention comprises, in general, a casing I9, including -a main-or central body l2, an end member. I4 and an end element I6, a rotor I'I and piston units I9.

The body I2 forms an inner chamber I8 for the vrotor I1 and for a lubricating fluid, such as oil,

and open at one side 20, at the left as viewed in rFigure 3, and is provided with a plurality of radial cylinders 22 disposed about and open to the chamber I8. A Wall 24, closing the opposite side of the chamber I8, provides an inner bearing pocket or receiving means for an anti-friction bearing 23. The body alsocomprises inlet yalve chambers 28, in this instance fora luidrof low lubricative character, such as gasoline, to be pumped, each of the chambers 28 being disposed between two of the cylinders 22, and having a local inlet 30 from the closed side of the body I2, and a local duct 32 to a next adjacent cylinder, to the right or clockwise thereof, as viewed in Figure 1. The body I2 further comprises a local outlet 34 from each of the cylinders 22 'for the gasoline to the closed side of the body. Plugs 36 and 38 close the outer ends of the cylinders 22 and the valve chambers 28, respectively.

The end member |4, see Figure 3, secured to the closed side of the body i2, as by bolts 40, is provided with a main inlet 42 and a main outlet 44 for the gasoline, a portion 46 of the member I4 cooperating with the wall 24 to provide a manifold 4l between the main inlet 42 and the local inlets 30. The member I4 has an outlet valve chamber 48 for each of the local outlets 34, and a manifold 50 between the main outlet 44 and each of the outlet valve chambers 48.

Poppet valve members 52 and 53, normally biased closed by springs 54 and 55, respectively, are disposed in the valve chambers 28 and 48, respectively.

The end element I6, secured to the open side 20 of the body l2, as by bolts 56, is provided with a counter-balance element receiving space l, bearing means or a portion 58 for receiving a bearing, and oil inlet and outlet ports 60 and 62, respectively, communicating with the chamber I8 of the body I2.

The rotor |1, as better shown in Figure 3, comprises a shaft S4 having one splined end 6B, for attachment. to a motor, and its opposite end splined into a portion 68 of the rotor. A portion 'I0 of the rotor supports the inner race of an anti-friction bearing 12, the outer race of which is disposed in a ring 'I4 press fitted in a recess in the end element I6 and having a flange 16.

Another ring 'I8 closely fits within the flange 'I6 and is connected to an annular end plate 80 by a bellows 82 xed and sealed relative to both the ring 18 and the plate B0, the latter of which is secured to the end element I6, as by screws 84.

To the right of the portion E8, as shown in Figure 3, the rotor Il further comprises a counterbalance weight sector 86 in the space 51, an eccentric cam portion 88 in the chamber I3, and a portion 90 supporting the inner race of the anti-friction bearing 23 in the pocket formed by the wall 24.

The rotor is provided with a bore 04 closed at one end 96 and open at its opposite end 88 to the oil in the inner chamber I8 of the body I2. The cam sector 83 has a peripheral slot |00 intersecting the bore 94 in communication therewith and with the oil in the chamber I0.

Each piston unit I9, as better seen .in Figure 2, comprises, in this instance, a piston or sleeve |02, in one of the cylinders 22, having an open spherically curved inner end |04, and an annular outer groove |06 communicating with the interior of the sleeve by a plurality of small radial holes |08. An auxiliary piston I I0, of substantially cupshape, has an annular exterior groove ||2, and port ||2 placing the interior of the auxiliary piston I|0 in communication with the groove ||2. The auxiliary piston |I0 has its closed end ||4 biased by a spring ||6 toward a lock ring I I8, which is disposed in an inner groove of the sleeve |02. The spring H6 extends. be.- tween the piston ||0 and an auxiliary sleeve |20 in the piston sleeve |02.

A link |22 is pivotally connected, 'at one end,

as by 'a pin |23, to the auxiliary sleeve |20 and to the piston sleeve |02, and has a cross portion |23', at the other end, linked to the shoe |24. The shoe has a recess conforming to, and slidably or pivotally receiving, the spherically curved end |04 of the sleeve |02, and a surface |25 conforming to the curvature of the cam 88. A recess |28, at the cam engaging side of the shoe |24, communicates, through an aperture |30 in the shoe, with the interior of the sleeve |02 and forms, in this instance, a substantially rectangular frame or flange |32 entirely around the recess |28 on the cam 88. The shoe |24 is further provided, in this instance, with arcuate opposite side grooves |34, Figures 1 and 3, in which are disposed rings I35. The latter are joined, axially of the cam, by clips |38, Figures l and 3, disposed between certain of the sleeves, to maintain the shoes in the various positions thereof determined by the cam 88.

In operation, when the rotor II rotates, each unit IS reciprocates, with the pistons |02 and IIB operating together, or in concert, to create a pumping action between the gasoline inlet and outet ports 42 and 44, respectively.

Referring to Figure 2, and assuming that there is resistance to the flow in the outlet line, as by the injection nozzles of a jet engine, with the unit I9 at the end of its gasoline discharge compression stroke, at the top of the unit, in Figure 2, at a position indicated by a broken line |48, the unit is full of oil and closed by the cam 88, since the slot |08 at this time has not reached the shoe |24. Also, the top of the auxiliary piston |I is in initial position spaced from the lock ring |I8 therebelow, as will further appear.

When the unit descends from this position, gasoline is drawn from the main inlet 42 into the manifold 4'I, and through the local inlet 30 to lift the valve member 52, and pass the liquid through the duct 32 into the cylinder 22. At this time, the outlet valve member 53 is maintained closed by the spring 55 and by the suction of the unit I9.

Upon continued descent of the unit I9, toward the end of its suction stroke shown in Figure 2, near this end or fastest part of its gasoline suction stroke, the slot |00 has arrived opposite the shoe |24, whereupon the auxiliary piston ||0 rises against the lock ring I I8 to create suction on the oil in the chamber I8 to draw into the unit I9 an amount of the oil equal to any which may have escaped along the cylinder walls between the latter and the unit I9.

When the unit is subsequently raised, from its position of Figure 2, the cam slot passes the shoe |24 to close off the oil communication with the chamber I8, whereupon the auxiliary piston gli@ pressing against the gasoline is returned to Y,initial position spaced from the lock ring I|8, during. which it exerts vpressure on the oil to force it through the ducts |08 into the groove v|238 wherein it forms, in effect, a piston ring of oil at a pressure dependent upon and relative to the pumping pressure of the gasoline preventing the passage of any substantial amount of either the gasoline or the oil through the clearance between the unit I9 and the walls of its cylinder 22.

The oil pressure, referred to above, may be rendered substantially equal, to the gasoline Apumping pressure because the effective area of vpiston H0, subjected to gasoline'pressure is equal to that subjected to oil pressure created by the a fluid to `be pumped communicating Withthe cylinder, an outlet valve from the cylinder for the iluid, a rotor including an eccentric cam having an opening for passing another fluid from said chamber, and a piston unit in the cylinder riding on the cam and open thereto and adapted to pump said first fluid and to, seal the unit against leakage thereof past the unit from its pumping side to its opposite side through clearance between the unit and the cylinder, the unit including a plurality of piston elements movable together in pumping said rst lluid and adapted, and having movement relative to each other dependent upon the pressure of said llrst lluid, to pump force said second fluid from said chamber through the cam opening to position between said piston elements sealing said clearance at a pressure relative to the pumping pressure of said first iluid preventing the passage of any substantial amount of either uid through said clearance, the cam being adapted to open and close said unit to said chamber.

4. In a pump including a cylinder, the combination of a piston unit adapted for operation in the cylinder to pump a fluid and to seal the unit against leakage of the fluid past the unit from its pumping side to its opposite side through clearance between the unit and the wall of the cylinder, said unit comprising a plurality of pumping piston elements movable together in the aforesaid pumping action and adapted, and having relative movement, to effect another pumping action dependent upon the pressure of said fluid, operating means for the unit including means supplying another fluid to the opposite side of said unit from a source separate from said piston unit, said other pumping action forcing said other fluid into position sealing said clearance at a pressure proportional to but greatel` than the pumping pressure of said rst fluid preventing the passage of any substantial amount of either fluid through said clearance.

5. In a pump including a chamber, the combination of a unit adapted for operation in the chamber to pump a fluid and to seal the unit against leakage of the iluid past the unit from its pumping side to its opposite side through clearance between the unit and the Wall of said chamber, said unit comprising a plurality of pumping elements movable together in the aforesaid pumping action and adapted, and having relative movement, to ellect pumping action dependent upon the pressure of said iluid to force another fluid into position sealing said clearance at a pressure relative to the pumping pressure of said rst fluid preventing the passage of any substantial amount of either fluid through said clearance, and an apertured shoe through which said second fluid passes to said position, and operating means for the unit including a cam on which the shoe rides and which controls the passage of said second fluid through the shoe.

6. In a pump including a chamber, the combination of a piston unit adapted for operation in the chamber to pump a fluid and to seal the unit against leakage of the lluid past the unit from its pumping side to its opposite side through clearance between the unit and the Wall of said chamber in which the unit operates, said unit comprising a plurality of pumping piston elements movable together in the aforesaid pumping action and adapted for relative movement to each other dependent upon the pressure of said fluid, operating means for the unit including means supplying another fluid to the opposite sidejof said unit from a source separate from said piston unit, said relative movement of said piston elements under the pressure of said rst fluid' forcing said other fluid into position sealing said clearance at a pressure relative to the pumping pressure of said first fluid preventing the passage dof any substantial amount of either fluid through said clearance, one of said piston elements being of substantially sleeve formation openat said pumping side, and another thereof closing the sleeve opening adjacent to said pumping side.

. .7. In a pump including a chamber, the combination of a unit adapted for operation in the chamber to pump a nrst fluid and to seal the unit against leakage of the first fluid past the unit from its pumping side to its opposite side through clearance between the unit and the wall of said chamber, said unit comprising a plurality of pumping elements movable together in the aforesaid pumping action and adapted for relative movementl to effect a relative pumping action dependent upon the pressure of said fluid, spring means biasing one of said pumping elements in a direction opposing the pressure of said first fluid and assisting said pumping elements in said relative pumping movement, a source of a second fluid; and operating means for the unit including means for supplying said second fluid to the opposite side of said unit, said relative pumping action forcing said second iluid into position sealing said clearance at a pressure dependent upon and relative to the pumping pressure of said first fluid thereby preventing the passage of any substantial amount of either fluid through said clearance.

8. In a pump including a chamber, the combination of a unit adapted for operation in the chamber to pump a rst'lluid and to seal the unit against leakage of the ilrst fluid past the unit from its pumping side to its opposite side through clearance between the unit and the Wall of said chamber, said unit comprising, a source of a second fluid, a plurality of pumping elements movable together in the aforesaid pumping action and 'adapted for relative movement to effect a relative pumping action dependent upon the pressure of said llrst fluid to force said second fluid into position sealing said clearance at a pressure dependent upon and relative to the pumping pressure of said ilrst fluid preventing the passage of any substantial amount of either fluid through said clearance, and means for operating said unit including means for controlling and causing said second fluid to ow from said source of the opposite side of said unit at a predetermined position of the stroke of the unit.

9. ln a pump including a chamber, the combination of a unit adapted for operation in the chamber to pump a first iluid and to seal the unit against leakage of the first fluid past the unit from its pumping side to its opposite side through clearance between the unit and the wall of 'saidchambelz said unit comprising a source of a second fluid, a plurality of pumping elements movable together in the aforesaid pumping action `and adapted for relative movement to eifect a relative pumping action dependent upon thepressure of said ilrst fluid to force said second fluid from its source into position sealing said clearance at a pressure dependent upon and relative to the pumping pressure of said lrst fluid preventing the passage of a substantial amount of either fluid through said clearance, and operating means for said unit having passageway means from said source of the second iiuid to said clearance sealing position for said second iluid.

10. In a pump including a chamber, the combination of a unit adapted for operation in the chamber to pump a iirst uid and having in effect a piston ring groove to seal the unit against leakage of the first fluid past the groove from the pumping side of the unit to its opposite side through clearance between the unit and the Wall of said chamber, said unit comprising a source of a second fluid, means for supplying said groove with said second uid, and a plurality of pumping elements movable together in the aforesaid pumping action and adapted to have a relative movement to eiect a relative pumping action dependent upon the pressure of said rst uid to force said second fluid into said groove sealing said clearance at a pressure dependent upon and relative to the pumping pressure of said first fluid preventing the passage of any substantial amount of either fluid through said clearance.

11. In a pump including a chamber, the combination of a unit adapted for operation in the chamber to pump a first uid and to seal the unit against leakage of the rst iiuid past the unit from its pumping side to its opposite side through clearance between the unit and the wall said chamber, said unit comprising a source a second fluid, a plurality of pigrnping elements movable together in the aforesaid pumpaction and adapted to have a relative move- `nient V`to eiect a relative pumpinggraction de- ,pendent'upon the pressure of said rst iiuid to force said second fluid into position v{s'ealing said 'clearance at a pressure dependent upon and rela- ,tive to the pumping pressure of saijd rst fluid preventing the passage of any substantial amount of either fluid through said clearancej'and means *for supplying said second fluid to ythe opposite fside of said unit from said source aforesaid.

JAMES E. `BEVINS.

REFERENCES CITED y The following references are of record in the file of this patent:

UNITED STATES PATENTS 

